For much of this discussion, I am indebted to David L. Parnas, especially for his paper, "Software Engineering Programmes Are Not Computer Science Programmes," IEEE Software, November/December 1999.
Parnas, David L., "Software Engineering: An Unconsummated Marriage," Software Engineering Notes, November 1997.
Baines, Robin, "Across Disciplines: Risk, Design, Method, Process, and Tools," IEEE Software, July/August 1998, pp. 61 64.